One of the main applications of the invention, as in the above earlier application, is making extender devices that are implantable for a determined length of time beneath the scalp to diminish baldness, but other applications can be envisaged for the device of the invention wherever it is useful and/or necessary to stretch tissue, e.g. for diminishing wounds where it is necessary to be able to cover a damaged area with new skin, in particular when the original skin has been destroyed or damaged by burning, trauma, etc. . . .
With respect to so-called "male-pattern baldness", it is known that definitive hair loss affects one in three of men aged 50.
Such baldness forms a part of a group of conditions known medically as "cicatricial alopecias": it is related to progressive and premature atrophy of hair follicles, at the roots of individual hairs, and its origins are genetic and hereditary.
So far, no medical treatment has managed to treat male-pattern baldness, and no therapeutic solution of a medical kind can be considered earlier than age 30 to 50.
At present the only effective therapy is surgical, and more than 2 million Americans have had recourse to such surgery: this is done by surgically redistributing a fraction of healthy follicles that are genetically programmed to last throughout life. In practice, they constitute hair taken from around the tonsure.
For this purpose, essentially there are three techniques, namely: implants; reductions of the tonsure; and flaps; all three of which consist in moving healthy hair-carrying scalp to replace all or part of the bald scalp.
The present invention relates solely to the second and most recent technique of reducing tonsure; it makes it possible to achieve a clear improvement in results for extensive male-pattern baldness which constitute the major fraction of cases to be treated.
At present, three surgical techniques are used with or without special devices, each having success relating to the result obtained and satisfaction and appreciation of the people concerned:
The oldest method consists in directly eliminating a region of bald skin during a plurality of successive operations, in separating the margins of the wound from underlying portions of the scalp, and in moving the two edges of the wound towards each other from opposite sides of said wound. The two edges of the wound are closed together under tension by means of surgical sutures, thereby stretching the scalp and thus increasing the hair-carrying area at the expense of bald area. Thus, on average, it is possible to eliminate a 3 cm wide strip of bald scalp on each operation: four to six tonsure-reducing operations are then often required since there is a limit to skin elasticity and it is not reasonable to remove more than 3 cm at a time without running the risk of tearing. Nevertheless, in spite of this high number of operations, and even if said number is increased, the result cannot be improved any further, and it is possible in this way to eliminate only about half of the initially bald area.
That failure to reduce the bald scalp area completely is related to two important phenomena that are combined, that are well known, and that are already analyzed in the patent application referred to in the introduction. That surgical method of reducing tonsure therefore always leaves a region of baldness, and it is therefore necessary for it to be associated with implants, thereby naturally increasing the cost and the overall time of the procedure.
To eliminate the above phenomena, a second operative method was developed about 10 years ago, particularly in America, in which use is made of balloons placed beneath the hair-carrying scalp, which balloons are progressively inflated at regular intervals of time: the hair-carrying scalp is thus subjected to internal pressure and it expands and spreads. Once it is deemed to have been expanded sufficiently, the operation can be performed as described above by removing a strip of the bald region or even all of it, and the lips of the remaining zones can be sewn together edge-to-edge, in the proper place.
It is thus possible to eliminate the entire bald area, replacing it with the hair-carrying zones that have been expanded by the balloons. Nevertheless, it is necessary to expand the balloons themselves regularly two or three times a week in order to achieve progressive expansion of the hair-carrying skin without tearing it. This requires regular monitoring, and in any event the resulting deformation of the head makes that technique unusable on a large scale. The advantage of the technique is lost because of considerations and criteria relating to appearance and because of the difficulty in immobilizing people who must be isolated over long periods. In addition, there is always the danger of the balloon bursting and of the expansion regions being poorly monitored.
In order to avoid the above drawbacks, a third surgical method has been developed that makes use of special extender devices constituting the subject matter of the patent application mentioned in the introduction, which method has been developed over some time and has been tested with success. Such an extender device includes at least one resilient means whose external dimensions when in the active, extended position, are such that a fraction of its perimeter corresponds substantially to and overlies the edges of at least a fraction of the area of tissue to be treated. The resilient means is associated with at least two fastening means each secured to a respective opposite end of the device in the resilient direction of said resilient means, enabling the device to be fixed to said tissue along said edges.
Because such extender devices (also called "extenders" for short) provide selective surface stretching, good tonsure-reducing results are obtained with few operations, while retaining satisfactory appearance of the head during the treatment so as to enable the persons concerned to continue all normal activity. This is achieved without destroying follicles by ischemia of the surface layers of the hair-carrying scalp, as has been observed when using other techniques. When using such extenders, the same advantages of stretching living tissue such as hair-carrying scalp are to be found as when using balloons, but in this case, the enormous advantage lies in the fact that the progressive distortion and stretching of the scalp is obtained without any increase in volume, and thus without increasing area in unwanted directions, with the increase in area being obtained solely in given directions. There is thus no change to the apparent shape of the head when the tissue being stretched is hair-carrying scalp, and there is no stretching in directions that are not useful.
Furthermore since the active ends of the extender can be located exactly at the edges of the regions that are to be subjected to traction in order to change surface area, those regions that are not to be stretched are not subjected directly to said tension: thus, when stretching the scalp, there is no secondary stretching of bald areas, thereby improving the effectiveness of the system and the rapidity of its action. However, it is necessary to apply traction to hair-carrying regions that are distant from the edge of the bald region so that when extension is complete, i.e. when the extender has returned to its rest position, its ends then being at a certain distance apart, said distance corresponds to the length of hair-carrying regions situated and maintained within the ends.
Since such extender devices do not make it possible to move the ends close enough together or even into contact, it is necessary:
either, as mentioned above, to apply traction to the hair-carrying scalp from regions of tissue situated behind the actual edges of the bald regions so as to leave some of the hair-carrying scalp between the fastening systems, thereby giving rise to non-uniform stretching between treated regions situated beyond said fastening systems and non-stretched regions situated between them;
or else to perform at least one second operation and to finish off final uniting of the hair-carrying regions by an operation of the oldest type, as described above, but that may give rise to a scar that remains quite visible.
In the examples described in the document mentioned in the introduction, the lengthening capacity of the resilient means that interconnect that at least two fastening means requires a minimum rest width of said resilient means, thus corresponding to a distance of a size that may be proportional to the amount of extension capacity desired. This distance can indeed be reduced by fixing the fastening systems to wide supports that extend behind the fastening systems relative to their lines of fixture to the scalp and thus to their lines of traction, and by fixing the ends of the resilient means interconnecting the supports to the supports behind their fixing lines: it is thus possible to have resilient means of a length such that, firstly when at rest the two fixing lines of the fastening systems are as close to each other as possible, being at a fixed distance apart or even one against the other, and secondly, in extension, the longation obtained corresponds to that looked-for so that the two fastening systems are put into place at the edge of the region to be treated, which may then correspond to the region of hair-carrying scalp, while leaving only the bald region between the fastening means.
Nevertheless such a device of the earlier invention has two independent hook-supporting plates and the force urging them towards each other as applied to them by the resilient means which interconnects them tends to cause them to tilt relative to each other and thus relative to the surface of the tissue and of the scalp, and this can give rise to additional unattractive appearance; furthermore they are not very easy to put into place and since the supports are relatively large in area they give rise to frictional resistance to displacement, thereby slowing down the return of the fastening means to their rest position, thus increasing the duration of treatment.